Thank you very much, you helped me a lot。 I've sent the patch to gcc-patches and libstdc++ mailing list. The urls are as bellow https://gcc.gnu.org/pipermail/libstdc++/2023-July/056279.html https://gcc.gnu.org/pipermail/gcc-patches/2023-July/623686.html I'm very exciting about my first contribution, and changed back to my usual email address.
